The overall objective or long term goal of the proposed research is the accumulation of quantitated data describing the human chewing function in terms of frequency, duration and amplitude. These parameters and their existing variations must be established in "acceptable" or "normal" or "good" occlusions as best as these parameters can be morphologically defined in terms of dentition and skeletal pattern. Secondly, individual variation from time point to time point must be established for the same group. Thirdly changes associated with development must be established if growing dynamic states are to be investigated. Finally, given the above information the function of so called "abnormal" or "unacceptable" or "malocclusions" can be quantitated and compared. A stereo-photography system is being developed based on the use of a high-speed camera, whose view of a patient is split by prisms and mirrors to obtain stereo vision on each frame of film. LED are attached to lightweight frames located on the upper and lower jaw and show up as light spots on the film. A unique digitizing system is being devised to accelerate the data processing which includes three-dimensional matrix manipulation of data via a computer. Relative motion between the patients' jaws is displayed on a computer graphics screen.